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W. E. PRALL, Jr. MOTOR TOR STREET GARS.

No. 426,060. (Q Patented A131222, 1890.

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MOTOR TOR STREET GARS. N0. 426,060. Patented ApLIZZ, 1890.

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WITNESSES: INVENTOR,

(No Model.) 3 Sheets-Sheet 3. W. E..PR ALL, J1".

MOTOR TOR STREET GARS. No. 426,060. Patent-ed Apr. 22, 1800.

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I UNITED STATES PATENT OEEICE.

IVILLIAM E. PRALL, JR., OF VASHINGTON, DISTRICT OF COLUMBIA.

MOTOR FOR STREET-CARS.

SPECIFICATION forming' part of Letters Patent No. 426,060, dated April 22, 1890.

Application filed May 27, 1889. Serial No. 312,299. (No model.)

To all whom t may concern:

it known that I, VILLIAM E. PRALL, Jr., a citizen of the United States, and a resident of the city of Washington, in the District of Columbia, have invented certain new and useful Improvements in Steam-Motors for Street- Cars or other Tramway-Vehicles; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention is an improvement on the construction shown and described in United States Letters Patent granted to me November 20, 1888, Serial No. 393,263, and is fully disclosed in the following specification, of which the accompanying drawings form a part, and in which similar letters of reference indicate like or equivalent parts wherever found throughout the several views.

Figure l shows a street-car provided with one form of myimprovement, certain portions thereof being shown in section; and Figs. 2 and 3 are similar views of other forms thereof.

In applying my apparatus to a car or other vehicle,I may adopt either of the forms of construction shown in the drawings; and it is evident that other arrangements may be made and that a motor may be applied to a separate cab, which may be employed to draw one or more cars, if necessary, without departing from the spirit of my invention, as hereinafter described and claimed. The form of construction shown in Fig. l of the accompanying drawings, however, is not claimed herein, but is made the subject of a separate application hereinafter referred to.

Referring to Fig. l, A indicates a tank, filled, preferably, with superheated water; B, a steam generator and superheater, and C a steam-engine. These parts are preferably arranged as shown, the water-tank being under the rear portion of the car, the steam generator and superheater between the axle, and the engine underthe front portion or platform. The steam generator and superheater consists of one or more coils of pipe arranged in a casing, preferably cylindrical in shape, and properly covered to prevent radiation, the coil or coils being in communication with the water-tank and engine and arranged in the following manner:

A is a pipe communicating with the bottom of tank A, and provided with a cup-shaped vessel G, and a check-valve a, and an ordinary valve a', and a by-pass c, provided with a back-pressure safety-valve c. The pipes ZJ of the separate steam-coils communicate with the top of the cup G, and are provided with regulating or needle valves c.

b are pipes which communicate with the pipes b and with tank A through by-pass c. The pipes b within the steam-generating chamber are arranged in conical spiral coils, the upper end of the coil or spiral communieating with a steam-pipe I, which communicates with a steam-drum E. The steam-drum E is located within the escape-'flue of the hotair or steam-generating chamber, or it may be between the latter and the engine, or at any other points desired, and a pipe M, provided with a valve m, connects the drumE with the top of t-he tank A.

lI is a hydrocarbon or fuel tank, placed, preferably, at or on the top of the car, and 7L a pipe extending therefrom to a burner B of any preferred construction.

O is a small pipe, which communicates with the steam-drum, and also with the burner B', whereby steam is conveyed to the burner to assist in the vaporization and combustion of the hydrocarbon in the well-known manner, if the same should be thought necessary, though with my construction of steam-generator it is not probable that the use of steam for this purpose would be required.

L is a pipe, which forms a communication between the steam-drum and engine, and by which steam is supplied to the engine, and L an exhaust-pipe communicating with a condenser P on the top of the car. A lever S is provided with a rod R, which connects the lever S with valves m m in pipesL and M and valve n in the fuel-supply pipe, and a small pipe E', provided with a safety-valve, connects the steam-drum with the exhaust-pipe.

The car-axle and crank-shaft of the engine are connected by means of a chain belt and gear-wheels in the well-known way.

As hereinbefore stated, the burner B may be of any preferred construction, adapted to IOO the combustion of oil, vapor, oil and air, or oil and steam, or vapor and air or steam. I prefer, however, to arrange between the burner and steam-coils a layer of perforated firebrick or similar substance, which will receive the flame and direct heat from theburner in such a manner that nothing but hot air orA the highly-heated gases of combustion will pass through the perforations in the nre-brick and come in contact with the steam-coils, the

object being to prevent the pipes from being a overheated and destroyed in case the water is discharged from them, leaving them filled only with steam. I also contemplate the use, 1n connection with the construction shown and described herein, of a small ignition burner or jet, the same as in the patent hereinbeforel referred to, whereby the main burner may be instantly ignited the moment the fuel-supply is turned on, the ignition-jets being always burning when the car is in use.

In the operation of this apparatus the tank A is iilled at a station provided for the purpose, preferably with superheated water, but

may be iilled with cold water,which would soon become heated by the passage of steam from the steam generator and superheater to the Watertank, as hereinafter described. When the tank A is filled, if the lever S be manipulated so as to open valves m, m', and n', and valve a be opened, the water in tank A would, by its own gravity, be forced through pipe A into the cup G, and through small valves e into the steam-coils. The water would seek the same level in the steam' coils as in tank A. At the same time the oil in tank I-I would pass through pipe h to the burner, and, being ignited, would begin the generation of steam within the coils. Valve m in pipe Mbeing open, the steam would pass directly into tank A, Where it would maintain the same pressure as in the generator,`

the effect of which would be to cause the Water to maintain a level'within the coils l) the same as that in tank A at all times, Whether a the pressure be high or low, providing that the communicating valves a', m, and e are not so controlled as to prohibit a flow of wa- Y Yterequal to the generation and utilizationof desired to stop the engine, the lever S is manipulated so as to close the valves m, m', and n', and the flow of the steam to the engine and tank A through pipe M is cut o, as is also the flow of oil to the burner. If at this time the pressure in the coils should increase beyond the point desired, the steam or water will be forced back through pipes b and pipes c into tank A, and the pressure in the tank and coils willfthus beequ-alized. The ilow of oil to the burner being' cut off at the same time as the flow of steam to the engine, it is probable that there will never be any overpressure in the coils caused by cutting off the ow of vsteam to the engine. The pipe c is provided with a back-pressure safety or check valveso constructed as to allow the steam or Water to be forced back into tankAwhenever the pressure in the coils shall be excessive, as herein stated, and the relief-pipe E', connecting the steam drum and exhaust, is intended -as an additional means for relieving overpressure, the safety-valve therein being set for a pressure greater than that of c.

The check-valves, regulating-valves, and other details of lconstruction may beof any preferred form, they constituting no part of this invention, and means ,for heating thecar by the exhaust-steam 4from the engine may also be provided, as shown in Fig. 2.

In the form shown in Fig. 2, the construction, location, vand operation 4of the various portions of the apparatus are substantially the same as in Fig. 1 with the exception of the means for supplying pressure in the water-tank, thus 4causing a proper V supply of water to the coils of the steam-generator, and is only necessary when cold .water is used. In this figure, anair-pump K is provided,vand a pipe K', which Yconnects said pump with the top of the water-tank. The-Valvesm and n in the pipes L and h `control the flow of the steam to the engine and the oiltothe burner, as in the yconstruction shown in Fig. l. The tank being filled with water and valve a being opened, the water will flow through pipe A ,valves e, and pipes b' into the steamcoils. The valve a is so constructed as to allow Water to pass freely from the tank to the coils, but prevent its return till the press,- ure in the coils exceeds a given amount and is sufficient to operate the engine, at which time the air-pump K will also' be put in mo.- ti'on, and the pressure ofthe air within the tank A may be retained at any degree re.- quired to force the water from said tank into the steam-coils, and an over degree'of airpressure may be prevented by means of a safety-valve m.. The generation of steam and the operation of other portions of the appaf ratus is the same as in Fig. 1

In Fig. 3 a circulating-water pump K is employed instead of the air-'pump shown in Fig. 2, and a by-pass c, provided with a checkvalve, whereby water may be conveyed from tank A Varound the pressure-valve `ct in pipe A to supply Water to the generator. When water is admitted to the steam-coils, the lever S is manipulated so as to admit oil to the burner and ysteam to the engine, when the `pump is also put in motion, and water is taken through pipe K to the pump and back through pipe K and valve K into the cup Gr, and thence through the pipesb and valves e into the steam-coils. So long as the press- IOO IIO

ure of steam in the coil is less than the pressure required to open the relief-valve d the Water will continue to go from the pump into the steam-coil; but so soon as the pressure in the coils becomes greater than the pressure required to open the valve a, then the Water will refuse to pass through valves e into the steam-coils, and Will find its passage into the tank A through the relief-valve d, thus supplying Water to the coil only as it is evaporated.

That form of construction shown in Fig. l of the accompanying drawings is not claimed herein, but is made the subject of a separate application, Serial No. 327,17 7, tiled October 1G, 1889.

Having fully described my invention, its construction and operation, what I claim, and desire to secure by Letters Patent of the United States, is-

1. In a motor for street-cars or other vehicles, the combination of a water-supply tank, a steam-generator consisting of separate coils, a cup or Vessel G inV communication With the supply-tank and with the coils of the generator, an engine in communication with the generator, a pump connected With said engine and operated thereby, and a pipe forming a communication between the pump and the supply-tank, and a second pipe forming a communication between the pump and the cup or vessel G, substantially as and `for the purposes set forth.

2. In a motor for street-cars or other Vehicles, the combination of a water-supply tank, a steam-generator consisting of a coil or coils, a cup or vessel, as G, 'in communication With the generator and with the tank, an engine in communication with the generator, a pump connected with said engine and operated thereby, and pipes forming acommunication between the supply-tank and the pump, and the cup or vessel G, substantially as shown and described.

3. In a motor for street-cars and other vehicles, the combination of a Watersupply tank, a steam-generator in communication therewith by means of a pipe provided with a regulating-Valve, as a, said pipe being also provided with a by-pass c, having a valve c', an engine in communication with the generator, and a pnmp'connected with said engine and operated thereby, and a pipe forming a communicationbetween the supply-tank and the pump, substantially as and for the purposes set forth.

4. The combination, in a motor for streetcars or other Vehicles, of a water-supply tank, a steam-generator communicating with said supply-tank by means of a pipe, as A', provided With pressure-regulating valve, a steamengine in communication with the steamgenerator, a pump, and a pipe forming a communication between said pump and the supply-tank for the purpose of producing pressure in said tank, and a by-pass in the pipe forming a communication between the supply-tank and the generator, provided with a Valve, substantially as shown and described.

5. The combination, in a motor for streetcars or other vehicles, of a Water-supply tank, a steam generator consisting of a coil or coils of pipe in communication with said tank by means of a pipe A', an engine in communication with the generator, a pump in communication with the supply-tank by means of a pipe K', and a by-pass pipe c, said pipes A and c being provided With valves, substantially as shown and described.

Signed at the city of IVashington this 27th day of May, A. D. 1889.

WILLIAM E. PRALL, JR.

W'itnesses:

RoBT. MASON, JAMES H. GRIDLEY. 

